Melanin is prepared through the conversion of Tyrosine into DOPA, Dopaquinone by the action of Tyrosinase located in the chromatophore then through the non-enzymatic oxidation. Melanin is distributed over the skin and has an important function to protect the body from various stimuli. However, it has been reported that excess production of melanin is closely related to melanoma and may also induce melanistic skin freckles, etc. Accordingly, a variety of cosmetics and medicaments for the prevention of excess production of melanin are actively developed in these days.
As the preventive agent for the excess production of melanin, hydroquinone has been mainly used heretofore. This compound, however, also exhibits side effects such as degeneration or lethal mutation of melanin, damage of the cellular function, etc., and therefore the use of hydroquinone in cosmetics is now prohibited in Korea, Japan, etc.(see, J. Soc. Cosmet. Chem., 42, 361, 1991). In addition, arbutin, a sugar derivative of hydroquinone, was commercialized but has been identified as having little whitening effect, and ascorbic acid, kojic acid, etc. have so poor product stability that they can only be restrictively used. While, extracts from licorice root, mori cortex radicis, etc. have been widely known to have a skin-whitening effect since ancient times. But, those extracts occasionally have poor effect according to the place of production it is difficult to keep the quality of the product constant(see, Fragrance J., 6, 59, 1990). Carzinol F extracted from a paper mulberry tree(see, Chem. Parm, Bull., 34(5), 1968, 1986; Cosmetics & Toiletries, 101, 51, 1995) was recently commercialized due to its good inhibitory activity against tyrosinase. However, this substance also has the problem that it is difficult to keep the quality of the product constant because carzinol F is an extract too. Sufficient data on stimulating property and stability of carzinol F are not available and it has a demerit that it cannot be easily synthesized because of the prenylcatechol group included therein.